G:\mplayer>mencoder "mf://data/*.png" -mf fps=25 -ovc raw -o test.avi
MEncoder Sherpya-SVN-r23169-4.1.2 (C) 2000-2007 MPlayer Team
CPU: Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz (Family: 6, Model: 15, Stepping: 6)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
success: format: 16  data: 0x0 - 0x0
MF file format detected.
[mf] search expr: data/*.png
[mf] number of files: 191 (764)
[demux_mf] file type was not set! trying 'type=png'...
VIDEO:  [MPNG]  0x0  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:16  fourcc:0x474E504D  size:0x0  fps:25.00  ftime:=0.0400
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffpng] vfm: ffmpeg (FFmpeg PNG decoder)
==========================================================================

Flushing video frames.
Filters have not been configured! Empty file?
Writing index...
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not writing vprp header.

Video stream:   -1.#IO kbit/s  (-2147483648 B/s)  size: 0 bytes  0.000 secs  0 frames